Topographical, three-dimensional models provide a physical representation of the landform.
The models can be created using a copy of the drawings of the terrain as a reference during model construction or by using a three-dimensional modeling program on a computer to generate a model data.
Traditionally, topographical models are made from a high-density foam, plastic foam, acetate, etc. The models must be enclosed to prevent people from touching. The purpose of these models is to see the features of terrain but not to touch them.
The most important disadvantages of the physical models are the inability to measure the elevational differences of the terrain in any point of the model and the lack of accuracy.
To show the elevational differences of the terrain, some of the models are created in stair-stepping style. Other models, are created by printing detailed photo-realistic images on the models carved from a high-density foam. These models can provide a physical representation of the terrain, but they are not made for easy Visual measuring because of the lack of an elevation reference, and they are not comparable to the accuracy of the three-dimensional computer-generated drawing.